Subsurface irrigation systems are well known and have been in use for many years. For example a U.S. Pat. No. 953,080 of Wiggins discloses an irrigation pipe that supplies water to a main conduit and a series of upwardly directed nozzles and a plurality of covers with one cover for each nozzle to protect the nozzle form becoming clogged.
A more recent patent, U.S. Pat. No. 4,721,408 of Hewlett discloses a water distribution system characterized by a construction including an irrifluent pipe disposed below the soil surface for dispersing water or treated waste water at a controlled rate. The irrifluent pipe includes an inner fluid conduit having apertures formed therethrough and an outer cover mounted in partially surrounding relation to the inner conduit and overlying the apertures. The outer cover is attached to the inner fluid conduit in spaced apart relation thereto so that the dispersed fluid slowly seeps into the ground.
A further U.S. Pat. No. 5,350,251 of Daniel discloses a system for controlling the moisture content of a planted surface. The system includes a plurality of drain conduits located beneath the planted surface for collecting liquid from the planted surface. The system also includes a sealed collection tank coupled to the plurality of drain conduits. The collection tank is located beneath the planted surface to collect liquid passing through the plurality of drain conduits. The system also includes a vacuum pump coupled to the collection tank for removing air from the collection tank for removing air from the collection tank to provide a suction force in the collection tank and in the plurality of drain conduits to draw a liquid from the planted surface through the plurality of drain conduits and into the collection tank. An elevated air tank is coupled between the vacuum pump and the collection tank. The elevated air tank is located at a remote location spaced apart from the collection tank. The vacuum pumps remove air from the air tank which causes the suction force on the air tank, in the collecting tank, and in the plurality of drain conduits. Soil moisture sensors automatically operate programs for favorable turf growth and playing conditions.
A still further U.S. Pat. No. 5,938,372 of Lichfield discloses another subsurface irrigation apparatus and method wherein the method and apparatus include an underlayment of water resistant material which also serves as a mounting surface for the remaining elements of the subsurface irrigation apparatus. Water is supplied to the subsurface irrigation apparatus through a water supply conduit and distributed through a plurality of water distribution conduits. Each water distribution conduit includes a plurality of spaced holes through which the irrigation water is distributed by the water distribution conduits. A diffuser is mounted across each hole to diffuse the water into the surrounding soil Each diffuser is includes a layer of fibrous material partially covered by a water resistant overlayment. The fibrous layer diffuses the water outwardly from the hole while simultaneously inhibiting root encroachment into the hole. A layer of course sand may be overlayed across said subsurface irrigation apparatus for helping diffuse the water into the soil, particularly those soils having a high content of clay. A valve and a controller to control the valve are also included. A moisture sensor can also be used to sense the moisture level in the soil to activate the controller.
Finally, a U.S. Pat. No. 6,712,552 of Kepler et al. discloses an economical and easily installed irrigation system for agricultural products covering large areas. The invention comprises top and bottom layers of geosynthetic material having a non-cohesive, porous material between the layers. A water distribution system is also placed between the layers. This system can be placed directly on the area to be irrigated without digging a trench or hole. Agricultural products such as turf or row crops are placed within top soil directly on the system.
Notwithstanding the above it is presently believed there is a need and a potential commercial market for an improved subsurface irrigation system for an athletic or agricultural field in accordance with the present invention. There should be a need for such systems because they are durable and provide year round irrigation of such fields and can be used to obtain an athletic field in pristine condition, for use in conduction sports events and healthy ground cover.